SIST EN 4575:2020

Overview

SIST EN 4575:2020 is a European standard developed by CEN that specifies the technical requirements for the aerospace-grade heat resisting alloy X12CrNiCoMoW21-20. This standard applies to solution-treated and descaled sheets and plates with thicknesses greater than 3 mm and up to 50 mm. Designated as FE-PA4901 by the Aerospace and Defence Industries Association of Europe (ASD-STAN), SIST EN 4575:2020 ensures consistent quality and performance of this specialized alloy for critical aerospace applications.

The heat resistant alloy X12CrNiCoMoW21-20 features a high-performance composition optimized for strength and oxidation resistance at elevated temperatures. The standard governs chemical composition, mechanical properties, heat treatment methods, and testing protocols essential for aerospace manufacturers and suppliers. SIST EN 4575:2020 aligns with other aerospace series material standards to provide cohesive guidance on metallic materials used in demanding environments.

Key Topics

• Material Specification: Defines chemical composition limits for elements including carbon (0.08–0.16%), chromium (18.5–21%), nickel (19–21%), molybdenum (2.5–3.5%), cobalt (18.5–21%), tungsten, niobium, manganese, silicon, phosphorus, sulfur, and nitrogen.

• State and Form: Applies to hot-rolled sheets and plates that are solution-treated and descaled, maintaining thickness between greater than 3 mm and 50 mm.

• Mechanical Properties: Sets minimum proof stress (Rp0.2 ≥ 305 MPa), tensile strength range (690–880 MPa), elongation at break (≥ 40%), and hardness limits (HV ≤ 235).

• Heat Treatment: Mandates solution treatment between 1100 °C and 1180 °C with a minimum holding time of 12 minutes followed by air cooling to achieve the desired metallurgical state.

• Quality Assessments: Encompasses visual testing for external imperfections and ultrasonic testing for internal flaws to aerospace quality Class 4 for thicknesses between 3 mm and 20 mm.

• Testing and Inspection: Refers to EN 4700-001 for the technical specifications regarding test sample preparation, dimensional and marking inspection, microstructure, and grain size requirements ensuring compliance with aerospace industry standards.

Applications

SIST EN 4575:2020 is critical for aerospace engineering and manufacturing sectors where components are exposed to high temperatures and demanding service conditions. Typical applications include:

• Aerospace structural components requiring exceptional heat resistance and mechanical strength.

• High-performance engine parts such as turbine sections, combustor liners, and exhaust components.

• Gas turbine and rocket engine assemblies where thermal stability and oxidation resistance are paramount.

• Aerospace sheet and plate materials used for manufacturing parts subject to thermal cycling and mechanical stresses.

By complying with SIST EN 4575:2020, manufacturers ensure the reliability and longevity of aerospace components made from X12CrNiCoMoW21-20 alloy, contributing to safer and more efficient aircraft operation.

Related Standards

• EN 4700-001: Aerospace series - Steel and heat resisting alloys - Wrought products - Technical specification for plates, sheets, and strips. Complements SIST EN 4575:2020 by detailing test methods and inspection criteria.

• EN 4258: Aerospace series - Metallic materials - General organization of standardization. Provides the framework for the structure and use of material standards in the aerospace sector.

• EN 4500-003: Aerospace series - Metallic materials - Rules for drafting and presentation of material standards - Part 003: Specific rules for heat resisting alloys. Defines the general drafting principles applicable to SIST EN 4575:2020.

Implementing these harmonized standards facilitates international cooperation, quality assurance, and interoperability within the aerospace materials industry.

Keywords: SIST EN 4575:2020, heat resisting alloy, X12CrNiCoMoW21-20, aerospace material standard, solution treated alloy, descaled sheets and plates, aerospace grade metal, heat resistant aerospace alloys, CEN aerospace standards, ASD-STAN FE-PA4901, aerospace component materials.